mybatis sqlSession（）。selectmap返回Map <key，map <key，value>＆gt;而是Map <ky，value>

Question

最近我们已经从ibatis升级到mybatis。

我们使用ibatis queryformap方法返回Map对象。 由于它已升级到mybatis，我们正在使用releavant函数selectmap。 但它返回Map<key,Map<key,value>>而不是Map<ky,value>。 我的代码。

DAO.java

public Map<String, Date> getCoverageDateList(Long personId,
        Date coverageEffectiveDate) {
    Map<String, Object> map = new HashMap<String, Object>();
    map.put("personId", personId);
    map.put("coverageEffectiveDate", coverageEffectiveDate);


    return getDataAccessTemplate().selectMap("Quote.getCoverageDateList", map, "productType");

}

Quote.xml

<select id="getCoverageDateList" parameterType="java.util.Map" resultMap="coverageMap">

SELECT
distinct 
    ql.productType
    ,q.coverageEffectiveDate as coverageDate
FROM Coverage cv inner join Quote q on q.quoteId = cv.quoteid
inner join  Quoteline ql on ql.lineid=cv.quotelineId
where
(cv.customerpersonid = #{personId} or cv.customerpersonid = @personId)
and (#{coverageEffectiveDate} between cv.rateEffectivedate and cv.rateTerminationDate)
</select>

    <resultMap id="coverageMap" type="java.util.HashMap">
    <result property="productType" column="productType"/>
    <result property="coverageDate" column="coverageDate"/>
</resultMap>

有人可以帮忙。